The present invention relates to programmable thermostats having remote temperature sensing inputs from wireless temperature sensing transmitters.
The present state of the art in digital programmable thermostats presents operational flexibility unknown with prior art analog mechanical devices. As shown in U.S. Pat. No. 5,449,319, a compact, low voltage programmable thermostat may have multiple operating modes available to the user. It is preferable that temperature sensing means transmit from various locations inside and outside a temperature controlled location the ambient temperature to the programmable thermostat. An important limitation in placing temperature sensing means in the several locations where they may be useful in control or providing information to the user through the programmable thermostat is that such temperature sensing means require power to sense and wirelessly transmit the temperature information. Such power is known to be adequately supplied with direct wiring to the general AC power supply available in each location. However, such direct wiring is often difficult and expensive to install in retrofit applications. The preferred locations of the temperature sensing means in a room or building exterior location may be effectively eliminated due to difficulty and/or expense of providing direct wiring.